Thermal Solutions EVS SERIES - Component Function

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A. SAFETY AND OPERATING CONTROLS. OPERATION AND SHUT DOWN
Component Function
Circuit Board Fuse
If the power draw of the control circuit exceeds approximately 5 amps, the circuit board
fuse trips and prevents the boiler from operating until the fuse is replaced.
Power Switch
If this switch is in the off position, power is interrupted to the control circuit of the boiler,
which prevents the boiler from operating. If the switch is in the on position, power is
supplied to the control circuit.
Operating Aquastat
If the boiler water temperature exceeds the adjustable set point, power is interrupted to
the control circuit of the boiler, which prevents the boiler from operating. When the boiler
water temperature drops below the set point minus the adjustable differential setting, power
is again supplied to the control circuit.
Manual Reset High
Limit Aquastat
If the boiler water temperature exceeds the adjustable set point, power is interrupted to the
control circuit of the boiler, which prevents the boiler from operating. Power is interrupted
until the control is manually reset by pressing the control’s reset button. When the button
is depressed, power will again be supplied to the control circuit.
Flow Switch
If the water ow through the boiler drops below the xed ow rate required to move the
control’s paddle enough to close the controls contacts, power is interrupted to the control
circuit, which prevents the boiler from operating. When the water ow rate is increased,
the paddle closes the control’s contacts and power is supplied to the control circuit.
Pressure (Safety)
Relief Valve
If the pressure inside the appliance exceeds the xed set point, the valve opens
mechanically and discharges water. The valve remains open until the pressure inside the
appliance drops below the set point.
Mixer Fuseable Link
If the temperature in the interior of the burner exceeds the xed set point. The contacts of
the switch open and power is interrupted to the control circuit, which prevents the boiler
from operating. Power is interrupted until the switch is replaced.
Vestibule Fuseable
Link
If the temperature in the interior of the vestibule enclosure exceeds the xed set point, the
contacts of the switch open and power is interrupted to the control circuit, which prevents
the boiler from operating. Power is interrupted until the switch is replaced.
High and Low Gas
Pressure Switches
If the gas pressure reaches a point below the adjustable set point, or above the adjustable
set point, the contacts of the switch open and power is interrupted to the control circuit,
which prevents the boiler from operating. Power is interrupted until gas pressure is
between the high and low set points and the control is manually reset by moving the switch
to the reset position. The switches will not reset until the gas pressure is within the set
point parameters.
Combustion Air Flow
Switch
If the differential air pressure drops below the xed set point, the contacts of the switch
open and power is interrupted to the control circuit, which prevents the boiler from
operating. Power is interrupted until air ow increases so that the contacts close.
Flame Safeguard
Control
Refer to the manual supplied with the boiler.
Variable Frequency
Drive (VFD)
The variable frequency drive’s primary function is to vary the rotational speed of the blower
fan based on the air requirements of the boiler combustion process. The VFD responds to
a 0-10 VDC signal from the TSBC.
Thermal Solutions
Boiler Control™
(TSBC)™
The Thermal Solutions Boiler Control™ (TSBC™) is a complete boiler and automation
system. It provides advanced boiler modulation control, operating control, diagnostics,
multiple boiler lead lag and auxiliary device control. Refer to the TSBC manual shipped
with the boiler to learn more about these features and functions.